1. Field of the Invention
The present invention relates to a liquid-encapsulated bushing including an elastomeric member disposed between outer and inner sleeves having axes parallel to each other. A plurality of liquid chambers are defined to face the elastomeric member and communicate with one another through orifices, so that the radial relative movement of the outer and inner sleeves is buffered by a resistance due to a liquid passing through the orifices.
2. Description of the Related Art
FIG. 7 shows a conventional liquid-encapsulated bushing. As can be seen from FIG. 7, the conventional liquid-encapsulated bushing B includes an outer sleeve 01 and an inner sleeve 02 having an axis L. First and second liquid chambers R.sub.1 and R.sub.2 are defined by the outer sleeve 01, a first elastomeric member 04 which interconnects a collar 03 fitted over an outer periphery of the inner sleeve 02 and by a pair of second elastomeric members 06 coupled to the outer sleeve 01 through spacers 05. The first and second liquid chambers R.sub.1 and R.sub.2 are connected to each other by two orifices O.
When the first elastomeric member 04 is deformed by a load to cause the outer and inner sleeves 01 and 02 to be relatively moved in directions of arrows X and X', the volumes of the first and second liquid chambers R.sub.1 and R.sub.2 are alternately increased and decreased. The liquid in the first and second liquid chambers R.sub.1 and R.sub.2 flows between the second and first liquid chambers R.sub.2 and R.sub.1 through the orifices O. Thus, the load is buffered by a resistance, due to the liquid, generated during the flowing of the liquid. When a further larger load is input to cause the outer and inner sleeves 01 and 02 to be moved largely relative to each other, the first elastomeric member 04 is brought into close contact with one of the second elastomeric members 06, thereby inhibiting the increase in amount of relative movement of the outer and inner sleeves 01 and 02 to exhibit a stopper function.
In the above conventional bushing, when the input load is small and the amount of relative movement of the outer and inner sleeves 01 and 02 is small, the volumes of the first and second liquid chambers R.sub.1 and R.sub.2 are effectively increased and decreased to provide a sufficient damping force. However, when the first elastomeric member 04 is brought into close contact with one of the second elastomeric members 06 by an increase in input load to establish a state which permits the stopper function to be exhibited, a problem arises in that the volumes of the first and second liquid chambers R.sub.1 and R.sub.2 are varied very little and thus provide an insufficient damping force.